Adjustable tension master feed finger



Feb. 20, 1962 w. D. CORLETT, JR 3,022,083

ADJUSTABLE TENSION MASTER FEED FINGER Filed July 51, 1959 2 Sheets-Sheet g IN VEN TOR.

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United States Patent 3,022,083 ADJUSTABLE TENSION MASTER FEED FINGER Webster D. Coriett, 312, River Forest, 111., assignor to Corlett-Turner (10., Franklin Park, 111., a corporation of Iliinois Filed July 31, 1959, Ser. No. 830,891 8 Claims. (Cl. 279-55) This invention relates to an adjustable tension'master feed finger for use on automatic screw machines or the like.

One purpose of the present invention is to provide an improved means for positioning and securing a stock piece in a master feed finger of the type described herein.

Another purpose is to provide an improved spring element for use in a feed finger of the type described.

Another purpose is to provide a feed finger in which the tension on a stock piece held therein may be increased or decreased without using any specialized tools.

Another purpose is to provide a master feed finger for use on automatic screw machines, including improved means for securing stock pieces of varying size and shape therein.

. Another purpose is to provide a master feed finger-of the type deseribed'having improved means forapplying pressure to a stock piece held therein.

Other purposes will appear in the ensuing specification, drawings and claims.

The invention is illustrated diagrammatically in the following drawings wherein:

FIGURE 1 is a plan view of a master feed finger or" the type described herein,

FIGURE 2 is an axial section along line 2-2 of FIG- URE 1,

FIGURE 3 is a lateral section along line 3-3 of FIG- URE 2, 3

FIGURE 4 is a lateral section along line 44 of FIG- DRE 2, FIGURE 5 is a side elevation of the improved spring element disclosed herein,

FIGURE 6 is a left end View of the spring element of FIGURE 5 and,

FIGURE 7 is a right end view of the spring element of FIGURE 5. Y

Referring now' to FIGURES 1 'and"2, a typical screw machine feed tube indicated at 10 has a chamber or bore 12' in which a stock piece 14 and a master feed finger of the type described herein are secured. A portion of the wall of the chamber 12 is threaded, as at 16, to receive a threaded portion 18 of a generally cylindrical body rnember 29 having an axial bore 21 therein. Agenerally cylindrical nut member 22 is rotatably mounted on the body member 20 and is threadedly engaged therewith by means of the threaded portion 18.

As clearly shown in FIGURES l and 2, the nut member 22 has an annular end surface 24 which is in contact with a similar annular end surface 26 of the screw machine feed tube 10. The nut member 22 has a pair of oppositely disposed generally flattened side portions 28 which may be tool gripping surfaces or the like. In many forms of feed fingers heretofore known, it was necessary to use special tools to make adjustments to the feed finger. In the feed finger disclosed herein all adjustments may be made with standard wrenches and no specialized tools are necessary.

The opposite end of the nut member 22 has a circumferential outer flange 30 which defines a circumferential recess or groove 32 which may receive one end of the spring members hereinafter described. It should be noted that the groove 32 has an outwardly tapered surface 34 so that the groove may more securely hold the spring members.

3,022,083 Patented Feb. 20, 1962 ice The body member 20' has an outwardly projecting surface portion 36 having a greater diameter than the main part of the body member and which defines an annular end wall 38 which may contact the end wall of a cap member hereinafter described. Adjacent the portion 36 of the body member are a pair of annular grooves or recesses 40 and 42, intermediate of which, is a threaded portion 44 which provides means for the cap member to be secured to the body.

As can be clearly seen in FIGURE 3 there is a pluralit in this case two, axial grooves or slots 46 in the body which receive spring members 48. The inner surface of each of the slots 46 is somewhat arcuate in shape so that the spring members, which are also arcuate at this partic: ular point, may be smoothly received therein. The body member is completed by an annular end wall 52 which cooperates with the cap member to define an annular chamber 54 surrounding the stock piece 14. r v s The cap member 56 is generally cylindrical in form and is hollow throughout. One end of the inner surface of the cap member is threaded, as at 58, so that the cap may be secured by the threads 44 of the body member. The outer diameter of the cylindrical cap is generally equal to the outer diameter of the portion 36 of the body member. The end wall 62 of the. cap member has a generally central aperture 64 which allows the stock piece 14 to project out of the feed finger so that workjoperations may beper formed thereon. The cap member is-completed by a pair of oppositely disposed generally flattened surfaces 60 which are similar to the flattened surfaces 28 on'the nut member and provide a tool gripping-surface for the cap member. I

The spring members 48, which will be described in detail hereinafter, are each disposed within the annular chamber 54 definedby the cap member and the end surface 52 and have'an axially extending portion 66 which is received within a slot 46 in the body member." The slot 46 has sutiicient depth so that the springs maybe com pletely received therein. It should be noted that the axially extending portion 66 is, inpart, within the cap member, but extends axially along the body beyond the cap. The end 67 of eachspring'member isin engagement with and is received within the circumferential groove or recess 34 in the nut member. i

- Positioned between the spring members 48 and the stock piece 14 are a plurality, in this case two,"pad members or pad elements 68. It should be 'understood'the invention is not limited to the 'use of only two springs and two pads as this number is merely'for purposes of illustration. I may use two or more springs and pads as the important thing is that I provide a means to apply equal radial pressure to the stock piece. In the particular form of the invention shown in the drawings, the-pad members are generally semi-circular in shape as the stock piece is a circular rod. However the particular shape and the size of the .pad members or elements will vary depending upon the size and shape of the stock piece. The pad elements each have an inner curved surface 70 which is a stock gripping surface and an axial slot 72, clearly shown in FIGURE 4, which is adapted to receive a spring member. The spring members bear against the pad elements and supply the pressure for the pad elements to grip the stock piece held therein.

Turning now to FIGURES 5 6 and 7, the springelement 48 is more clearly shown. v The spring member-has a generally flattened portion 74 which is recei ved within q tion 74 is" generally flattened, both the portions 76 and 78 and the axially extending portion 66 are generally arched or arcuate in shape: As the pressure brought to bear upon the spring elements is end Wise or axial, it is.

essential that these portions of the spring element be somewhat-arcuate in order that they will not buckle or" distort when pressure is applied thereto. The generally flattened portion 74 exerts pressure radially inward or towards the pad and therefore does not have to be arenate in shape. 7 i

The'u'se', operatic and function of the invention are asfollowsz' a a The adjustable tension master feed finger shown herein is particularly applicable for use on automatic screw machines; however, the device as shown and described has other'applications. It has several advantages in ,use on screw machines in that in many forms of feed fingers heretofore known, the adjustments necessary to increase the tension had to be made with special tools. In the improved feed finger shown herein the adjustments necessary' to increase or decrease'the tension may be made with standard wrenches'. Additionally my feed finger is very sensitive in adjustment as I am able to adjust the tension on the stock from parti'cally nothing up to a pressure sufficient to prevent the fingers movingv over the bar at all under normal conditions. Inusing my adjustable feed finger, the pad members are first chosen to fit the size and shape of the stock piece to be used. The paid members are assembled on the stock piece and the'spring's are then positioned so that the pads bear against the, stock piece. Next the cap and body members are assembled and the cap member isscrewed up tight until it bearsagainst the end wall 38 on the body member; The springs, pads and stock piece'are then secured in position within the feed finger. Next the nut member 22 is screwed on the opposite end of the body member and is turned up until the circumferential flange 30' encloses theiends of the spring members in the annu lar' groove 32; As the nut member is tightened it moves toward the spring members and so forces or applies pressure to' the generally flattened portion 74 of the spring members; As the' pressure is supplied the flattened por-.

tion moves radially-inward and presses down upon the 4 a stock piece positioned therein, a portion of said body member extending within said cap member and defining an annular chamber therewith, a plurality of spring members positioned within said chamber and adapted to apply pressure to a stock piece positioned therein, said spring members each having a portion extending axially along said body member and partlywithin said cap member, said nut member having an end surface bearing against the axially extending portion of said spring members to apply pressure thereto, rotation of said nut member on said body member being effective to increase or decrease the pressure applied to said spring members.

2. The structure of claim 1 further characterized in that said body member has a plurality, of. axial grooves whichreceive said spring members, and said springs each have an end. surface bearing against said cap member.

3. The structure, of claim 1 wherein said nut member end surface has a circumferential flange which overlies the end of the axial portion of said spring members.

4. A- feed finger for use on automatic screw machines or the like including a generally cylindrical body having an axial bore therein and a generally cylindrical hollow cap member rotatably mounted thereon adjacent one end thereof, said feed finger adapted to have a stock piece positioned therein, said body having an end surface cooperating with said cap member. to define an annular chamber, a plurality of pad members positioned in said chamber, said pad membershaving an inner surface thereof'formed to contact.v a stock piece, a plurality of spring members axially disposed in said'chamber and positioned tobear against said. pad members, said spring members having a portion extending axially along said body, and anut member rotatably' mounted .on said body 1 adjacent the opposite end thereof, said nut member havpad members and so securely positions and holds the stock piece in the feed finger. The nut member is turned until the desired amount of tension has been applied to the padsto securely hold the stock in place. The feed finger and the stock are completely assembled and the body member need only be screwedinto the screw machine feed tube to complete the assembly of the unit.

.Ofpartieular advantage in my construction is the shape of the spring elements. .The generally flattened portion provides a good pressure bearing surface for the pads and the stock piece. The other portions of the springs are generally arcuate so that the spring elements may'receive pressure in a longitudinal or axial direction without buckling. By having the ends of the spring elements fitted within an annular groove. or inside a circumferential flange 30 the spring elements are securely held and may be easily tension'ed by turning the nut member 22.

Whereas I have shown the preferred form of the invention it should be realized there may be many modifications, substitutions and alterations thereto without departing from the scope'of the following claims. -I claim: 7 1'.- A feed finger for use on automatic screw machines or the like including a body member having an axial bore extending" therethrough, a nutmember and a hollow cap member" rotatably mounted on said body member at opposite ends thereof, said feed finger adapted to have ing an end surface adapted to bear against'the axially extending portion of said spring members to apply pressure thereto, rotation of said out member thereof on said body member being effective to increase or decrease the pressure applied to'said spring members.

5. The structure of claim 4 wherein said nut member has a circumferential grooverec'eivi'ng the axially extending portion of said spring members. 7

6. The structure of claim 4 wherein the'p'orti'on of each of said spring members contactingsaid pad memhers is: generally hat, the portion of said spring-members adjacent said flat portion being generally upturned, one of said upturned portions extending axially along said body member.

7. A spring member for use in. adjustable tension feed fingers including a generally flattened portion adapted to apply pressure to a member positioned against one side thereof, generally upturned portions adjacent each end ofsaid flattened portion, said upturned portions being directed awayfrom said pressure applying flattened portion, a generally elongated portion extending from one of said upturned portions, said elongated portion being longer than said pressure applying flattened portion and forming a smaller angle with said-flattened portion than i said upturned portions.

8. The spring member of claim 7 wherein said upturned portions andsaid' generally elongated portion are slightly arcuate.

References Cited in the file of this patent UNITED STATESPATENTS Parsons July 21, 1959 

